Apparatus for treating antimony ores.



H. L. HERRENSGHMIDT.

APPARATUS FOR TREATING ANTIMONY ORES.

APPLICATION FILED 001'. 1, 1908.

953, 142. Patented Mar.29,1910.

Flg 4 Q. i zwu q v we UNITED STATES PATENT OFFICE.

HENRI LOUIS HERRENSOHMIDT, OF PARIS, FRANCE.

APPARATUS FOR TREATING ANTIMONY v()RES.

Specification of Letters Patent.

Original application filed June 14, 1907, Serial No. 379,050. Dividedand this application filed October 1, 1908.

To all whom it may concern:

Be it known that I, IIENRI LOUIS HERREN- SCHMIDT, a citizen of theFrench Republic, and resident of Paris, France, have invented certainnew and useful Improvements in Apparatus for Treating Antimony Ores, ofwhich the following is a specification.

The object of my invention is to provide an apparatus for treatingantimonious ores containing arsenic to recover the antimony completelyfreed from arsenic in whatever proportions the latter may be present.

According to my invention the arsenical antimony ore previously coarselygraded or crushed is treated in the roasting furnace so as to cause itto give off a mixture of oxid of antimony and arsenious acid togetherwith sulfur dioxid which is separated and subsequently utilized ashereinafter described. The roasting of the ore is performed at a lowtemperature say at about 400 deg. C. in order to obviate anyagglomeration ofresiduein the furnace to permit of the employment ofcast metal apparatus and to reduce fuel consumption. The' finely dividedores are mixed either with carbonate of soda and lime, with soda wasteto which has been added carbonate or sulfate of soda, or with sulfid ofsodium. The mixture thus obtained is charged into an autoclavecontaining water which is then boiled until the pressure reaches aboutfour or five atmospheres. Durin this operation there is formed a mixtureof antimoniate or sulfo-antimoniate of soda (or both) and of arsenate orsulfo-arsenate of soda (or both). After the completion of this operationthe contents of the autoclave are discharged into a vat-andsa liquortitrating 2 to 8 deg. Be. is drawn ofi' containing the above-mentionedmixture of antimoniate or sulfo-antimoniate of soda and arsenate orsulfo-arsenate of soda (or both). This liquor is then caused to reactwith the mixture of oxid of antimony and arsenious acid result ing fromthe above-mentioned furnace treatment of the coarse ore. In thisreaction there are formed oxids or sulfids of antimony (or both) whichremain mixed with the acids of antimony first obtained while the arsenicdissolves in the solution containing the sulfo-arsenate of soda (orboth) and the antimoniate of sulfo antimoniate of soda in excess. Thesulficls and oxids of antimony thus freed from arsenic may be collootedby filtration or by decantation and are thereafter mixed with a flux andfused whereby regulus of antimony free from arsenic is obtained. Theantimony contained by the liquor into which the arsenic has passed isthen separated therefrom, either by means of the sulfur dioxiddisengaged during the roasting of the coarse ore, or by means of anyother suitable acid, .sulfid of antimony being thus formed, whilearsenate or sulfo-arsenate of soda mixed with sulfate of soda remain inthe solution. Sulfid of antimony is separated and is either convertedinto oxid or reduced to the metallic form. The sulfite of soda isfinally freed from arsenate, or sulfo-arsenate of soda bycrystallization.

An example of the apparatus is illustrated in the accompanying drawing,in which Figure 1 is a longitudinal section; Figs. 2 and 3 aretransverse vertical sections/on lines AA and BB respectively of Fig. '1,and Fig. 4 is a horizontal section online CC of Fig. 1.

As shown in Fig. 1, the apparatus comprises in the first place aroasting furnace a provided with hollow fire bars 6 arranged in stepsand symmetrically disposed so as to permit the residues, freed fromantimony and arsenic to easily fall through the .grate as the roastingproceeds. T he ore is mixed in the furnace with a very small quantity ofcoke, say from 3 to 5%, with the object of conducting the roasting ataslow a tempe 'ature as practicable, viz., about 400 deg. (1, underwhich condition the volatilization of the antimony and arsenic may beeffected without any agglomeration of the residues being occasioned, thelatter remaining in a divided state which permits of their easywithdrawal from between the firebars.

The low temperature under which the volatilization of the arsenic andantimony is effected renders it possible to employ pipes c of cast ironfor conducting the gases directly from the furnace outlet to the con-(lensing apparatus. The condensing apparatus is constituted by a seriesof masonry or by metal (wrought or cast iron) chambers or compartments(Z surmounted and connected by ribbed or gilled pipes e whereof eachpair connecting consecutive chambers or compartments cl are connectedPatented Mar. 29, 191.0.

by unions as illustrated. Each chamber 03 is provided at its lower partwith a door 9 to enable the oxids of antimony and arsenious acid to beremovedas they become condensed and while the furnace is in operation.The gases (sulfurous acid, OXlCl of antimony and uncondensed arseniousacid) are drawn off by means of aspirators h and driven into the base ofa reaction tower i. The liquor containing the antimoniate orsulfo-antimoniate of soda and arsenate or sulfo-arsenate of sodaresulting as above described from the treatment of the finely dividedores in the autoclave, is fed into the upper part of this tower by thepipe j and falls on to the tippler is whereby it is discharged instreams on to the coke below. The said liquor falls through the cokeinto the tank Z situated at the lower part of the tower, a constantlevel being maintained in said tank by overflowing through a launder minto the aspirators h, whence it escapes to a receptacle. The liquorwhich overflows from the tank at a constant level Z into the aspirator hand which contains oXid and sulfid of antimony in suspension in sodiumsulfite and arsenate or sulfo-arsenate finally flows into the settlingtanks a.

The above described arrangement of apparatus ofiers the followingadvantages. 1st. The winning of antimony completely free from arsenicwhatever proportion of the latter may be present in the ore treated.2nd. Economy in fuel consumption. 3rd. The employment of cast iron inthe construction of those parts of the apparatus in immediate proximityto the eXit of the furnace, thus lessening the cost of the installation,rendering the apparatus less cumbrous and capable of being quicklyerected, and when necessary taken down and reerected. 4th. Thepossibility of collecting the oxids of antimony and the arsenious acidas they are condensed without interfering with the operation of thefurnace. 5th. The quick starting and stopping of the operation and thestopping thereof without inconvenience.

The apparatus may be employed equally well for treating other ores ofzinc, mercury and the like.

My present application is a division of one filed by me on or about June14th, 1907, Serial No. 379,050.

arsenious acid as they are condensed while the furnace is at work; areaction tower t adapted to be traversed from top to bottom by analkaline and arsenical liquor and from bottom to top by sulfurous acid;suction apparatus interposed between the condensing apparatus and thereaction tower for the purpose of promoting the flow of gases traversingthe condensing apparatus, causing said gases to mix with the liquorflowing from the reaction tower and finally driving the gases which haveescaped condensation into the reaction tower.

2. Apparatus for the treatment of ores, comprising a roasting furnacewith a hearth having stepped fire bars symmetrically arranged;condensing apparatus connected directly to the furnace by a cast ironconduit and constituted by a series of gilled or ribbed pipessurmounting and connecting precipitating chambers provided with meansfor withdrawing the oxids of antimony and arsenious acid as they arecondensed While the furnace is at work; a re-action tower adapted to betraversed from top to bottom by an alkaline and arsenical liquor andfrom bottom to top by sulfurous acid;

a conduit connecting the condensing apparatus with the tower, means forconveying liquor from the reaction tower to said conduit, means in saidconduit for causing suc tion for the purpose of promoting the flow ofgases traversing the condensing apparatus and for mixing said gases withthe liquor flowing from the react-ion tower and for finally driving thegases which have escaped condensation into the reaction tower.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

HENRI LOUIS HERRENSCHMID'I.

WVitnesses H. C. Coxn, MAURICE H. PIGUET.

